问题
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What legitimate reasons exist to overload the unary operator& ?
I just read this question, and I can't help but wonder:
Why would anyone possibly want to overload the & ("address-of") operator?
some_class* operator&() const { return address_of_object; }
Is there any legitimate use case?
回答1:
If you're dealing with any sort of wrapper objects, you might want or need to transparently forward the access to the wrapper to the contained object. In that case, you can't return a pointer to the wrapper, but need to overload the address-of operator to return a pointer to the contained object.
回答2:
Because they're evil and want you to suffer.
Or I guess if you are using proxy objects? I suppose you might want to return a pointer to the managed object instead of the container - although i'd rather do that with a getter function. Otherwise you'd have to remember to use things like boost::addressof.
回答3:
Yes, for debugging (if you want to trace any access or reference, you might want to put a log line on any call to &, * or ->).
回答4:
I have seen this in productive code already.
But there, a binary representation of the content of a struct was returned, not just 0.
And the usecase was simple: Binary operations.
来源：https://stackoverflow.com/questions/6499502/why-would-anyone-want-to-overload-the-address-of-operator